Review article: is non-alcoholic fatty liver disease a spectrum, or are steatosis and non-alcoholic steatohepatitis distinct conditions?

Vinpocetine and Lactobacillus improve fatty liver in rats: role of adiponectin and gut microbiome

Therapeutics that interfere with the damage/pathogen-associated molecular patterns (DAMPs/PAMPs) have evolved as promising candidates for hepatic inflammation like that occurring in non-alcoholic fatty liver disease (NAFLD). In the current study, we examined the therapeutic impact of the phosphodiesterase-1 inhibitor vinpocetine (Vinpo), alone or when combined with Lactobacillus, on hepatic abnormalities caused by a 13-week high-fat diet (HFD) and diabetes in rats. The results show that Vinpo (10 and 20 mg/kg/day) dose-dependently curbed HFD-induced elevation of liver injury parameters in serum (ALT, AST) and tissue histopathology. These effects were concordant with Vinpo's potential to ameliorate HFD-induced fibrosis (Histological fibrosis score, hydroxyproline, TGF-β1) and oxidative stress (MDA, NOx) alongside restoring the antioxidant-related parameters (GSH, SOD, Nrf-2, HO-1) in the liver. Mechanistically, Vinpo attenuated the hepatocellular release of DAMPs like high mobility group box (HMGB)1 alongside lowering the overactivation of the pattern recognition receptors including, toll-like receptor (TLR)4 and receptor for advanced glycation end-products (RAGE). Consequently, there was less activation of the transcription factor nuclear factor-kappa B that lowered production of the proinflammatory cytokines TNF-α and IL-6 in Vinpo-treated HFD/diabetes rats. Compared to Vinpo treatment alone, Lactobacillus probiotics as adjunctive therapy with Vinpo significantly improved the disease-associated inflammation and oxidative stress injury, as well as the insulin resistance and lipid profile abnormalities via enhancing the restoration of the symbiotic microbiota. In conclusion, combining Vinpo and Lactobacillus probiotics may be a successful approach for limiting NAFLD in humans.

Mechanism of PANoptosis in metabolic dysfunction-associated steatotic liver disease

In recent years, the incidence of metabolic dysfunction-associated steatotic liver disease (MASLD) has been steadily rising, emerging as a major chronic liver disease of global concern. The course of MASLD is varied, spanning from MASLD to metabolic dysfunction associated steatohepatitis (MASH). MASH is an important contributor to cirrhosis, which may subsequently lead to hepatocellular carcinoma. It has been found that PANoptosis, an emerging inflammatory programmed cell death (PCD), is involved in the pathogenesis of MASLD and facilitates the development of NASH, eventually resulting in inflammatory fibrosis and hepatocyte death. This paper reviews the latest research progress on PANoptosis and MASLD to understand the mechanism of MASLD and provide new directions for future treatment and drug development.

A novel Alisma orientale extract alleviates non-alcoholic steatohepatitis in mice via modulation of PPARα signaling pathway

Non-alcoholic fatty liver disease (NAFLD), particularly advanced non-alcoholic steatohepatitis (NASH), leads to irreversible liver damage. This study investigated the therapeutic effects and potential mechanism of a novel extract from traditional Chinese medicine Alisma orientale (Sam.) Juzep (AE) on free fatty acid (FFA)-induced HepG2 cell model and high-fat diet (HFD) + carbon tetrachloride (CCl4)-induced mouse model of NASH. C57BL/6 J mice were fed a HFD for 10 weeks. Subsequently, the mice were injected with CCl4 to induce NASH and simultaneously treated with AE at daily doses of 50, 100, and 200 mg/kg for 4 weeks. At the end of the treatment, animals were fasted for 12 h and then sacrificed. Blood samples and liver tissues were collected for analysis. Lipid profiles, oxidative stress, and histopathology were examined. Additionally, a polymerase chain reaction (PCR) array was used to predict the molecular targets and potential mechanisms involved, which were further validated in vivo and in vitro. The results demonstrated that AE reversed liver damage (plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatocyte ballooning, hepatic steatosis, and NAS score), the accumulation of hepatic lipids (TG and TC), and oxidative stress (MDA and GSH). PCR array analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that AE protects against NASH by regulating the adipocytokine signaling pathway and influencing nuclear receptors such as PPARα. Furthermore, AE increased the expression of peroxisome proliferator-activated receptor gamma coactivator-1α (PPARGC1α) and reversed the decreased expression of PPARα in NASH mice. Moreover, in HepG2 cells, AE reduced FFA-induced lipid accumulation and oxidative stress, which was dependent on PPARα up-regulation. Overall, our findings suggest that AE may serve as a potential therapeutic approach for NASH by inhibiting lipid accumulation and reducing oxidative stress specifically through the PPARα pathway.

Apelin and the gut microbiome: Potential interaction in human MASLD

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a leading cause of chronic liver disease with increasing numbers worldwide. Adipokines like apelin (APLN) can act as key players in the complex pathophysiology of MASLD.

AIMS

Investigating the role of APLN in MASLD.

METHODS

Fecal and blood samples were collected in a MASLD cohort and healthy controls (HC). MASLD patients with liver fibrosis and MASLD-associated hepatocellular carcinoma (HCC) were included into the study. Systemic concentration of Apelin, Apelin receptor (APLNR) and circulating cytokines were measured in serum samples.

RESULTS

Apelin concentration correlated with the Fib-4 score and was elevated in MASLD patients (mild fibrosis, mF (Fib-4 <3.25) and severe fibrosis, sF (Fib-4 >3.25)) as well as in MASLD-associated HCC patients compared to HC. In accordance APLNR and circulating cytokines were also elevated in mF and sF. In contrast apelin levels were negatively associated with liver survival at three and five years. Changes in taxa composition at phylum level showed an increase of Enterobactericae, Prevotellaceae and Lactobacillaceae in patients with sF compared to mF. We could also observe an association between apelin concentrations and bacterial lineages (phyla).

CONCLUSIONS

Circulating apelin is associated with liver fibrosis and HCC. In addition, there might exist an interaction between systemic apelin and the gut microbiome.

Nonalcoholic Fatty Liver Disease and the Intestinal Microbiome: An Inseparable Link

Nonalcoholic fatty liver disease (NAFLD) particularly affects patients with type 2 diabetes and obesity. The incidence of NAFLD has increased significantly over the last decades and is now pandemically across the globe. It is a complex systemic disease comprising hepatic lipid accumulation, inflammation, lipotoxicity, gut dysbiosis, and insulin resistance as main features and with the potential to progress to cirrhosis and hepatocellular carcinoma (HCC). In numerous animal and human studies the gut microbiota plays a key role in the pathogenesis of NAFLD, NAFLD-cirrhosis and NAFLD-associated HCC. Lipotoxicity is the driver of inflammation, insulin resistance, and liver injury. Likewise, western diet, obesity, and metabolic disorders may alter the gut microbiota, which activates innate and adaptive immune responses and fuels hereby hepatic and systemic inflammation. Indigestible carbohydrates are fermented by the gut microbiota to produce important metabolites, such as short-chain fatty acids and succinate. Numerous animal and human studies suggested a pivotal role of these metabolites in the progression of NAFLD and its comorbidities. Though, modification of the gut microbiota and/or the metabolites could even be beneficial in patients with NAFLD, NAFLD-cirrhosis, and NAFLD-associated HCC. In this review we collect the evidence that exogenous and endogenous hits drive liver injury in NAFLD and propel liver fibrosis and the progressing to advanced disease stages. NAFLD can be seen as the product of a complex interplay between gut microbiota, the immune response and metabolism. Thus, the challenge will be to understand its pathogenesis and to develop new therapeutic strategies.

Involvement of Lipophagy and Chaperone-Mediated Autophagy in the Pathogenesis of Non-Alcoholic Fatty Liver Disease by Regulation of Lipid Droplets

Non-alcoholic fatty liver disease (NAFLD) is defined as the accumulation of lipids in the form of lipid droplets in more than 5% of hepatocytes. It is regarded as a range of diverse pathologies, including simple steatosis and steatohepatitis. The structural characteristics of lipid droplets, along with their protein composition, mainly including perilipins, have been implicated in the etiology of the disease. These proteins have garnered increasing attention as a pivotal regulator since their levels and distinct expression appear to be associated with the progression from simple steatosis to steatohepatitis. Perilipins are target proteins of chaperone-mediated autophagy, and their degradation is a prerequisite for lipolysis and lipophagy to access the lipid core. Both lipophagy and chaperone-mediated autophagy have significant implications on the development of the disease, as evidenced by their upregulation during the initial phases of simple steatosis and their subsequent downregulation once steatosis is established. On the contrary, during steatohepatitis, the process of chaperone-mediated autophagy is enhanced, although lipophagy remains suppressed. Evidently, the reduced levels of autophagic pathways observed in simple steatosis serve as a defensive mechanism against lipotoxicity. Conversely, in steatohepatitis, chaperone-mediated autophagy fails to compensate for the continuous generation of small lipid droplets and thus cannot protect hepatocytes from lipotoxicity.

WITHDRAWN: Vinpocetine and Lactobacillus improve fatty liver in rats via modulating the oxidative stress, inflammation, adiponectin and gut microbiome

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Exercise Training and Probiotic Lacticaseibacillus rhamnosus GG Reduce Tetracycline-Induced Liver Oxidative Stress and Inflammation in Rats with Hepatic Steatosis

Lifestyle modification with regular exercise can improve metabolic diseases by reducing lipid profile and inflammation. Probiotics have been recently recommended not only for gastrointestinal diseases but also for metabolic and even degenerative diseases. Therefore, in the present study, the effect of high-intensity interval training (HIIT) and Lacticaseibacillus rhamnosus strain GG (LGG) as a probiotic on tetracycline-induced hepatic steatosis in an animal model was evaluated. Eighty male Wistar rats were randomly divided into eight groups (n = 10 in each group): control, LGG, HIIT, LGG + HIIT, tetracycline-induced (TTC), TTC + LGG, TTC + HIIT, and TTC + LGG + HIIT. The rats are treated by intraperitoneal injection (IP) with 140 mg kg-1 tetracycline, an antibiotic previously known to induce steatosis. The exercise training groups performed HIIT 5 days/week for 5 weeks, and 107 CFU/ml of Lacticaseibacillus rhamnosus GG was gavaged for the LGG groups 5 days/week for 5 weeks. Fatty droplets in the hepatocyte were considered with Oil Red staining. TTC-receiving rats have more lipid accumulation and larger lipid droplets in the liver compared to healthy animals. The two-way ANOVA showed that the interaction of LGG and HIIT significantly decreased LDL, cholesterol, and triglyceride in the healthy rats (p < 0.05). In TTC-receiving rats, the interaction of LGG and HIIT significantly increased HDL and SOD and significantly decreased triglyceride, ALP, AST, and ALT (p < 0.05). The consumption of probiotic LGG, along with HIIT with control of lipid profile and liver enzymes and improvement of the oxidative capacity, neutralizes the damage of TTC to liver tissue. Therefore, this protocol can be recommended for people with hepatic steatosis.

Novel approach using [18F]FTHA-PET and de novo synthesized VLDL for assessment of FFA metabolism in a rat model of diet induced NAFLD

BACKGROUND AND AIMS

The worldwide prevalence of Non-alcoholic Fatty Liver Disease (NAFLD) raises concerns about associated risk factors, such as obesity and type 2 Diabetes Mellitus, for leading causes of disability and death. Besides Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS), functional imaging with Positron Emission Tomography (PET) could contribute to a deeper understanding of the pathophysiology of NAFLD. Here we describe a novel approach using the PET tracer [18F]FTHA, which is an analog of long-chain free fatty acids (FFA) and is taken up by tissues to enter mitochondria or to be incorporated into complex lipids for further export as very-low-density lipoprotein (VLDL).

METHODS

Male Sprague Dawley rats, after 6 weeks on a high-fat diet (HFD), were used as a model of diet induced NAFLD, while a standard diet (SD) served as a control group. Liver fat was estimated by MR spectroscopy at a 9.4 T system for phenotyping. To measure hepatic FFA uptake, rats underwent 60 min dynamic [18F]FTHA-PET scans after unrestricted access to food (HFD: n = 6; SD: n = 6) or overnight (≤16h) fasting (HFD: n = 6; SD: n = 5). FFA removal was assessed from incorporated 18F-residual in de novo synthesized VLDL out of plasma.

RESULTS

MRS of the liver confirmed the presence of NAFLD (>5.6% fat). Under non-fasting conditions, hepatic [18F]FTHA uptake was significantly increased in NAFLD: SUVmean (p = 0.03) within [0; 60] min interval, SUVmean (p = 0.01) and SUVmax (p = 0.03) within [30; 60] min interval. SUVs for hepatic uptake under fasting conditions were not significantly different between the groups. Analysis of FFA removal demonstrated elevated values of 18F-residue in the VLDL plasma fraction of the healthy group compared to the NAFLD (p = 0.0569).

CONCLUSION

Our novel approach for assessing FFA metabolism using [18F]FTHA demonstrated differences in the hepatic FFA uptake and FFA incorporation into VLDL between healthy and NAFLD rats. [18F]FTHA-PET could be used to study metabolic disturbances involved in the progression of NAFLD.

Experimental Data on the Role of Melatonin in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Despite the increasing prevalence of nonalcoholic fatty liver disease (NAFLD) worldwide, its complex pathogenesis remains incompletely understood. The currently stated hypotheses cannot fully clarify the interrelationships between individual pathogenetic mechanisms of the disease. No appropriate health strategies have been developed for treating NAFLD. NAFLD is characterized by an accumulation of triglycerides in hepatic cells (steatosis), with the advanced form known as nonalcoholic steatohepatitis. In the latter, superimposed inflammation can lead to fibrosis. There are scientific data on NAFLD's association with components of metabolic syndrome. Hormonal factors are thought to play a role in the development of metabolic syndrome. Endogenous melatonin, an indoleamine hormone synthesized by the pineal gland mainly at night, is a powerful chronobiotic that probably regulates metabolic processes and has antioxidant, anti-inflammatory, and genomic effects. Extrapineal melatonin has been found in various tissues and organs, including the liver, pancreas, and gastrointestinal tract, where it likely maintains cellular homeostasis. Melatonin exerts its effects on NAFLD at the cellular, subcellular, and molecular levels, affecting numerous signaling pathways. In this review article, we discuss the experimental scientific data accumulated on the involvement of melatonin in the intimate processes of the pathogenesis of NAFLD.

Nutritional Approaches in Children with Overweight or Obesity and Hepatic Steatosis

Childhood obesity is a global public health problem. Worldwide, 41 million children under 5 years and 340 million children and adolescents between 5 and 19 years are overweight. In addition, the recent COVID-19 epidemic has further amplified this social phenomenon. Obesity is a condition associated with various comorbidities, such as nonalcoholic fatty liver disease (NAFLD). The pathophysiology of NAFLD in obesity is intricate and involves the interaction and dysregulation of several mechanisms, such as insulin resistance, cytokine signaling, and alteration of the gut microbiota. NAFLD is defined as the presence of hepatic steatosis in more than 5% of hepatocytes, evaluated by histological analysis. It can evolve from hepatic steatosis to steatohepatitis, fibrosis, cirrhosis, hepatocellular carcinoma, and end-stage liver failure. Body weight reduction through lifestyle modification remains the first-line intervention for the management of pediatric NAFLD. Indeed, studies suggest that diets low in fat and sugar and conversely rich in dietary fibers promote the improvement of metabolic parameters. This review aims to evaluate the existing relationship between obesity and NAFLD in the pediatric population and to assess the dietary patterns and nutritional supplementations that can be recommended to prevent and manage obesity and its comorbidities.

1,25-Dihydroxycholecalciferol down-regulates 3-mercaptopyruvate sulfur transferase and caspase-3 in rat model of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of liver morbidity and mortality and has multiple unclear pathogenic mechanisms. Vitamin D deficiency was associated with increased incidence and severity of NAFLD. Increased hepatic expression of 3-mercaptopyruvate sulfur transferase (MPST) and dysregulated hepatocyte apoptosis were involved in NAFLD pathogenesis. We aimed to explore the protective effect of 1,25-Dihydroxycholecalciferol (1,25-(OH)₂ D3) against development of NAFLD and the possible underlying mechanisms, regarding hepatic MPST and caspase-3 expression. 60 male adult rats were divided into 4 and 12 week fed groups; each was subdivided into control, high-fat diet (HFD), and HFD + VD. Serum levels of lipid profile parameters, liver enzymes, insulin, glucose, C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and hepatic levels of malondialdehyde (MDA), total antioxidant capacity (TAC), and reactive oxygen species (ROS) were measured. BMI and HOMA-IR were calculated, and liver tissues were processed for histopathological and immunohistochemical studies. The present study found that 1,25-(OH)₂ D3 significantly decreased BMI, HOMA-IR, serum levels of glucose, insulin, liver enzymes, lipid profile parameters, CRP, TNF-α, hepatic levels of MDA, ROS, hepatic expression of MPST, TNF-α, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and caspase-3; and significantly increased hepatic TAC in both HFD-fed groups. In conclusion: Administration of 1,25-(OH)₂ D3 with HFD abolished the NAFLD changes associated with HFD in 4-week group, and markedly attenuated the changes in 12-week group. The anti-apoptotic effect via decrement of caspase-3 and MPST expression are novel mechanisms suggested to be implicated in the protective effect of 1,25-(OH)₂ D3.

Association between perfluoroalkyl substances exposure and the prevalence of nonalcoholic fatty liver disease in the different sexes: a study from the National Health and Nutrition Examination Survey 2005-2018

There is evidence that perfluoroalkyl substances (PFASs) have effects on liver toxicity, and the effects may exhibit sex differences. Our study aims to explore the association between exposure to four PFASs (perfluorooctanoic acid, PFOA; perfluorooctane sulfonate, PFOS; perfluorohexane sulfonate, PFHxS; and perfluorononanoate, PFNA) and the risk of nonalcoholic fatty liver disease (NAFLD) in adults ≥ 20 years old in the US population. The data were based on the National Health and Nutrition Examination Survey (NHANES) 2005-2018. We used Poisson regression to explore the association between the four PFASs and NAFLD. We included 3464 participants; of these, 1200 (34.64%) individuals were defined as having NAFLD, and the prevalence of NAFLD was 39.52% in men and 30.40% in women. After Poisson regression, among the premenopausal and postmenopausal and total women, PFOA had a significantly positive association with NAFLD (p < 0.05). After principal component analysis, the "composite PFAS" was associated with NAFLD in postmenopausal and total women, and the RRs (95% CIs) were 1.306 (1.075, 1.586) and 1.161 (1.007, 1.339), respectively. In adults, we found that PFASs were associated with NAFLD, and the associations varied by sex, particularly for PFOA and PFNA, which had a positive association with NAFLD in women.

Icariin Alleviates Nonalcoholic Fatty Liver Disease in Polycystic Ovary Syndrome by Improving Liver Fatty Acid Oxidation and Inhibiting Lipid Accumulation

(1) Background: Icariin is the main component of the Chinese herb Epimedium. A number of studies have shown that it alleviates abnormal lipid metabolism. However, it is not clear whether and how icariin can ameliorate hepatic steatosis with polycystic ovary syndrome (PCOS). This study was designed to explore the anti-hepatosteatosis effect of icariin in rats with polycystic ovary syndrome. (2) Methods: Female Sprague Dawley(SD)rats were treated with a high-fat diet and letrozole for 21 days to make nonalcoholic fatty liver disease (NAFLD) in the polycystic ovary syndrome model. Then model rats were treated with icariin (by gavage, once daily) for 28 days. Serum hormones and biochemical variables were determined by ELISA or enzyme. RNA-sequence analysis was used to enrich related target pathways. Then, quantitative Real-time PCR (qRT-PCR) and Western blot were performed to verify target genes and proteins. (3) Results: Icariin treatment reduced excess serum levels of Testosterone (T), Estradiol (E2), Luteinizing hormone (LH), Follicle-stimulating hormone (FSH), LH/FSH ratio, insulin, triglycerides (TG), and aspartate aminotransferase (AST) in high-fat diet (HFD) and letrozole fed rats. Meanwhile, icariin ameliorated HFD and letrozole-induced fatty liver, as evidenced by a reduction in excess triglyceride accumulation, vacuolization, and Oil Red O staining area in the liver of model rats. Results of RNA-sequencing, western blotting, and qRT-PCR analyses indicated that icariin up-regulated fatty acid translocase (CD36), in mitochondria, and peroxisome proliferator-activated receptor α (PPARα) expression, which led to the enhancement of fatty acid oxidation molecules, such as cytochrome P450, family 4, subfamily a, polypeptide 3 (CYP4A3), carnitine palmitoyltransferase 1 α (CPT1α), acyl-CoA oxidase 1 (ACOX1), medium-chain acyl-CoA dehydrogenase (MCAD), and long-chain acyl-CoA dehydrogenase (LCAD). Besides, icariin reduced lipid synthesis, which elicited stearoyl-Coenzyme A desaturase 1 (SCD1), fatty acid synthase (FASN), and acetyl-CoA (ACC). (4) Conclusion: Icariin showed an ameliorative effect on hepatic steatosis induced by HFD and letrozole, which was associated with improved fatty acid oxidation and reduced lipid accumulation in the liver.

The Role of Oxidative Inactivation of Phosphatase PTEN and TCPTP in Fatty Liver Disease

Alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are becoming increasingly prevalent worldwide. Despite the different etiologies, their spectra and histological feature are similar, from simple steatosis to more advanced stages such as steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Studies including peroxiredoxin knockout models revealed that oxidative stress is crucial in these diseases, which present as consequences of redox imbalance. Protein tyrosine phosphatases (PTPs) are a superfamily of enzymes that are major targets of reactive oxygen species (ROS) because of an oxidation-susceptible nucleophilic cysteine in their active site. Herein, we review the oxidative inactivation of two tumor suppressor PTPs, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and T-cell protein tyrosine phosphatase (TCPTP), and their contribution to the pathogenicity of ALD and NAFLD, respectively. This review might provide a better understanding of the pathogenic mechanisms of these diseases and help develop new therapeutic strategies to treat fatty liver disease.

A Physiologically Based Pharmacokinetic Model to Predict the Impact of Metabolic Changes Associated with Metabolic Associated Fatty Liver Disease on Drug Exposure

Metabolic associated fatty liver disease (MAFLD) is the most common chronic liver disease, with an estimated prevalence of between 20 and 30% worldwide. Observational data supported by in vitro and pre-clinical animal models of MAFLD suggest meaningful differences in drug disposition in MAFLD patients. This study aimed to build a physiologically based pharmacokinetic (PBPK) model reflecting observed changes in physiological and molecular parameters relevant to drug disposition that are associated with MAFLD. A comprehensive literature review and meta-analysis was conducted to identify all studies describing in vivo physiological changes along with in vitro and pre-clinical model changes in CYP 1A2, 2C9, 2C19, 2D6 and 3A4 protein abundance associated with MAFLD. A MAFLD population profile was constructed in Simcyp (version 19.1) by adapting demographic and physiological covariates from the Sim-Healthy population profile based on a meta-analysis of observed data from the published literature. Simulations demonstrated that single dose and steady state area under the plasma concentration time curve (AUC) for caffeine, clozapine, omeprazole, metoprolol, dextromethorphan and midazolam, but not s-warfarin or rosiglitazone, were increased by >20% in the MAFLD population compared to the healthy control population. These findings indicate that MAFLD patients are likely to be experience meaningfully higher exposure to drugs that are primarily metabolized by CYP 1A2, 2C19, 2D6 and 3A4, but not CYP2C9. Closer monitoring of MAFLD patients using drugs primarily cleared by CYP 1A2, 2C19 and 3A4 is warranted as reduced metabolic activity and increased drug exposure are likely to result in an increased incidence of toxicity in this population.

Low skeletal muscle mass is associated with more severe histological features of non-alcoholic fatty liver disease in male

BACKGROUND/PURPOSE OF THE STUDY

Although low skeletal muscle mass is associated with non-alcoholic fatty liver disease (NAFLD), it is currently uncertain whether there are associations between weight-adjusted appendicular skeletal muscle (ASM%), severity of histological features of NAFLD, and the patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 polymorphism. Our aim was to test for a possible influence of the PNPLA3 rs738409 variant on the association between ASM% and severity of NAFLD histological features.

METHODS

We enrolled 401 Chinese male with biopsy-proven NAFLD. Using a bioelectrical-impedance body composition analyzer (BIA, Inbody 720, Japan Inc., Tokyo), we calculated the ASM% as the percentage of total appendicular skeletal muscle mass (ASM, kg)/total body mass (kg) × 100.

RESULTS

Compared to those with high ASM%, patients with low ASM% (≤ 30.6, i.e., the median value of distribution of the whole sample) had a greater severity of individual histological features of NAFLD. These patients also had a higher risk of severe steatosis and non-alcoholic steatohepatitis (NASH) (adjusted-odds ratio [OR] 2.34, 95% CI 1.39-3.93, and adjusted-OR 2.22, 95% CI 1.30-3.77) even after adjusting for age, body mass index, diabetes, and serum creatinine levels. Carriage of the G allele of PNPLA3 rs738409 plus low ASM% was associated with a higher risk of severe steatosis and presence of liver fibrosis (OR 3.02, 95% CI 1.46-6.26, p = 0.003 and OR 2.18, 95% CI 1.03-4.60, p = 0.041 respectively), and there was a non-significant but borderline increased risk of NASH (OR 2.00, 95% CI 0.98-4.06, p = 0.056).

CONCLUSIONS

Low ASM% and the presence of a G allele within PNPLA3 rs738409 is associated with more severe histological features of NAFLD.

Age-Related NAFLD: The Use of Probiotics as a Supportive Therapeutic Intervention

Human aging, a natural process characterized by structural and physiological changes, leads to alterations of homeostatic mechanisms, decline of biological functions, and subsequently, the organism becomes vulnerable to external stress or damage. In fact, the elderly population is prone to develop diseases due to deterioration of physiological and biological systems. With aging, the production of reactive oxygen species (ROS) increases, and this causes lipid, protein, and DNA damage, leading to cellular dysfunction and altered cellular processes. Indeed, oxidative stress plays a key role in the pathogenesis of several chronic disorders, including hepatic diseases, such as non-alcoholic fatty liver disease (NAFLD). NAFLD, the most common liver disorder in the Western world, is characterized by intrahepatic lipid accumulation; is highly prevalent in the aging population; and is closely associated with obesity, insulin resistance, hypertension, and dyslipidemia. Among the risk factors involved in the pathogenesis of NAFLD, the dysbiotic gut microbiota plays an essential role, leading to low-grade chronic inflammation, oxidative stress, and production of various toxic metabolites. The intestinal microbiota is a dynamic ecosystem of microbes involved in the maintenance of physiological homeostasis; the alteration of its composition and function, during aging, is implicated in different liver diseases. Therefore, gut microbiota restoration might be a complementary approach for treating NAFLD. The administration of probiotics, which can relieve oxidative stress and elicit several anti-aging properties, could be a strategy to modify the composition and restore a healthy gut microbiota. Indeed, probiotics could represent a valid supplement to prevent and/or help treating some diseases, such as NAFLD, thus improving the already available pharmacological intervention. Moreover, in aging, intervention of prebiotics and fecal microbiota transplantation, as well as probiotics, will provide novel therapeutic approaches. However, the relevant research is limited, and several scientific research works need to be done in the near future to confirm their efficacy.

Oyster (Crassostrea gigas) Polysaccharide Ameliorates High-Fat-Diet-Induced Oxidative Stress and Inflammation in the Liver via the Bile Acid-FXR-AMPKα Pathway

Oyster polysaccharides (OPS) have a variety of biological activities. In this study, we aimed to investigate the potential mechanisms of OPS to ameliorate hepatic oxidative stress and inflammation in mice induced by a high-fat diet (HFD). The results showed that OPS reduced the HFD-induced increases in serum transaminase levels and alleviated hepatic oxidative stress and inflammation. Moreover, OPS regulated bile acid metabolism and increased bile acid content in the liver, serum, and feces. Serum bile acid profile results indicated that OPS reduced levels of chenodeoxycholic acid, deoxycholic acid, and lithocholic acid associated with high-affinity agonists of Farnesol X receptor (FXR). Western blot analysis showed that OPS accelerated bile acid metabolism by downregulating hepatic FXR expression and promoting its downstream CYP7A1, CYP27A1, and CYP8B1 protein expression. Meanwhile, OPS ameliorated oxidative stress and inflammation in the liver by modulating FXR-AMPKα-Nrf2/NF-κB signaling to reduce p-IκBα/IκBα, p-NF-κB p65/NF-κB p65, IL-1β, and TNF-α expression and increase p-Nrf2/Nrf2, HO-1, and NQO-1 expression. This study was the first to explore the possible mechanism of OPS in improving liver oxidative stress and inflammation from the perspective of bile acid metabolism, providing a theoretical basis for OPS as a new source of functional food.

Non-Alcoholic Fatty Liver Disease and Extrahepatic Cancers: A Wolf in Sheep’s Clothing?

Non-alcoholic fatty liver disease (NAFLD) is now considered the main driver and leading cause of chronic liver disease globally. The umbrella term NAFLD describes a range of liver conditions closely related to insulin resistance, metabolic syndrome, diabetes mellitus, obesity, and dyslipidemia. At the same time, several malignancies, including hepatocellular carcinoma and colorectal cancer, are considered to be common causes of death among patients with NAFLD. At first, our review herein aims to investigate the role of NAFLD in developing colorectal neoplasms and adenomatous polyps based on the current literature. We will also explore the connection and the missing links between NAFLD and extrahepatic cancers. Interestingly, any relationship between NAFLD and extrahepatic malignancies could be attributable to several shared metabolic risk factors. Overall, obesity, insulin resistance, metabolic syndrome, and related disorders may increase the risk of developing cancer. Therefore, early diagnosis of NAFLD is essential for preventing the progression of the disease and avoiding its severe complications. In addition, cancer screening and early detection in these patients may improve survival and reduce any delays in treatment.

Evaluation of Toxicant-Associated Fatty Liver Disease and Liver Neoplastic Progress in Sprague-Dawley Rats Treated with Low Doses of Aflatoxin B1 Alone or in Combination with Extremely Low Frequency Electromagnetic Fields

The term toxicant-associated fatty liver disease (TAFLD) has been proposed to describe fatty liver diseases connected to toxicants other than alcohol. Aflatoxins are mycotoxins commonly found as contaminants in foods and feeds, which are known liver toxicants and potential candidates as potential causes of TAFLD. Aflatoxin B1 (AFB1) was administered at low doses to Sprague-Dawley (SD) rats, alone or in combination with S-50 Hz an extremely low frequency electromagnetic field (ELFEMF), to study the evolution of TAFLD, preneoplastic and neoplastic lesions of the liver and the potential enhancing effect of lifespan exposure to ELFEMF. Steatosis, inflammation and foci of different types were significantly increased in both aflatoxin-treated males and females, which is consistent with a pattern of TAFLD. A significant increase in adenomas, cystic dilation of biliary ducts, hepatocellular hyperplasia and hypertrophy and oval cell hyperplasia were also observed in treated females only. The administration of low doses of AFB1 caused TAFLD in SD rats, inducing liver lesions encompassing fatty infiltration, foci of different types and adenomas. Furthermore, the pattern of change observed in preneoplastic liver lesions often included liver steatosis and steatohepatitis (TASH). ELFEMF did not result in any enhancing or toxic effect in the liver of SD rats.

Bile acid and receptors: biology and drug discovery for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), a series of liver metabolic disorders manifested by lipid accumulation within hepatocytes, has become the primary cause of chronic liver diseases worldwide. About 20%-30% of NAFLD patients advance to nonalcoholic steatohepatitis (NASH), along with cell death, inflammation response and fibrogenesis. The pathogenesis of NASH is complex and its development is strongly related to multiple metabolic disorders (e.g. obesity, type 2 diabetes and cardiovascular diseases). The clinical outcomes include liver failure and hepatocellular cancer. There is no FDA-approved NASH drug so far, and thus effective therapeutics are urgently needed. Bile acids are synthesized in hepatocytes, transported into the intestine, metabolized by gut bacteria and recirculated back to the liver by the enterohepatic system. They exert pleiotropic roles in the absorption of fats and regulation of metabolism. Studies on the relevance of bile acid disturbance with NASH render it as an etiological factor in NASH pathogenesis. Recent findings on the functional identification of bile acid receptors have led to a further understanding of the pathophysiology of NASH such as metabolic dysregulation and inflammation, and bile acid receptors are recognized as attractive targets for NASH treatment. In this review, we summarize the current knowledge on the role of bile acids and the receptors in the development of NAFLD and NASH, especially the functions of farnesoid X receptor (FXR) in different tissues including liver and intestine. The progress in the development of bile acid and its receptors-based drugs for the treatment of NASH including bile acid analogs and non-bile acid modulators on bile acid metabolism is also discussed.

The contribution of sterile inflammation to the fatty liver disease and the potential therapies

Hepatic inflammation is prevalent in several metabolic liver diseases. Recent scientific advances about the pathogenesis of metabolic liver diseases showed an emerging role of several damage-associated molecular patterns (DAMPs), including DNA, high-mobility group box 1 (HMGB1), ATP and uric acid. For these DAMPs to induce inflammation, they should stimulate pattern recognition receptors (PRRs), which are located in the hepatic immune cells like resident Kupffer cells, infiltrated neutrophils, monocytes or dendritic cells. As a consequence, proinflammatory cytokines like interleukins (ILs)-1β and 18 alongside tumor necrosis factor (TNF)-α are overproduced and released, leading to pronounced hepatic inflammation and cellular death. This review highlights the contribution of these DAMPs and PRRs in the settings of alcoholic and nonalcoholic steatohepatitis. The review also summarizes the therapeutic usefulness of targeting NLR family pyrin domain containing 3 (NLRP3)-inflammasome, Toll-like receptors (TLRs) 4 and 9, IL-1 receptor (IL-1R), caspase 1, uric acid and GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) in these hepatic inflammatory disorders.

Tilapia-Head Chondroitin Sulfate Protects against Nonalcoholic Fatty Liver Disease via Modulating the Gut-Liver Axis in High-Fat-Diet-Fed C57BL/6 Mice

We isolated and characterized tilapia-head chondroitin sulfate (TH-CS) and explored its biological activity and mechanisms of action as an oral supplement for nonalcoholic fatty liver disease (NAFLD) induced by a high-fat diet (HFD) in mice. The results showed that treatment with TH-CS for 8 weeks alleviated the development of NAFLD, as evidenced by the notable improvement in liver damage, blood lipid accumulation and insulin resistance (IR). Meanwhile, TH-CS treatment reduced the expression of proinflammatory cytokines and normalized oxidative stress. Additionally, the analysis of 16S rDNA sequencing revealed that TH-CS could restore gut microbiota balance and increase the relative abundance of short-chain fatty acid (SCFA)-producing bacteria. Furthermore, SCFAs produced by related bacteria can further improve lipid metabolism and IR by regulating lipid synthesis signals. In conclusion, TH-CS is an effective dietary supplement for the prevention of NAFLD, and may serve as a potential supplementary treatment for lipid-related metabolic syndrome.

Inflammation and Cancer: From the Development of Personalized Indicators to Novel Therapeutic Strategies

Colorectal (CRC) and hepatocellular carcinoma (HCC) are associated with chronic inflammation, which plays a role in tumor development and malignant progression. An unmet medical need in these settings is the availability of sensitive and specific noninvasive biomarkers. Their use will allow surveillance of high-risk populations, early detection, and monitoring of disease progression. Moreover, the characterization of specific fingerprints of patients with nonalcoholic fatty liver disease (NAFLD) without or with nonalcoholic steatohepatitis (NASH) at the early stages of liver fibrosis is necessary. Some lines of evidence show the contribution of platelets to intestinal and liver inflammation. Thus, low-dose Aspirin, an antiplatelet agent, reduces CRC and liver cancer incidence and mortality. Aspirin also produces antifibrotic effects in NAFLD. Activated platelets can trigger chronic inflammation and tissue fibrosis via the release of soluble mediators, such as thromboxane (TX) A2 and tumor growth factor (TGF)-β, and vesicles containing genetic material (including microRNA). These platelet-derived products contribute to cyclooxygenase (COX)-2 expression and prostaglandin (PG)E2 biosynthesis by tumor microenvironment cells, such as immune and endothelial cells and fibroblasts, alongside cancer cells. Enhanced COX-2-dependent PGE2 plays a crucial role in chronic inflammation and promotes tumor progression, angiogenesis, and metastasis. Antiplatelet agents can indirectly prevent the induction of COX-2 in target cells by inhibiting platelet activation. Differently, selective COX-2 inhibitors (coxibs) block the activity of COX-2 expressed in the tumor microenvironment and cancer cells. However, coxib chemopreventive effects are hampered by the interference with cardiovascular homeostasis via the coincident inhibition of vascular COX-2-dependent prostacyclin biosynthesis, resulting in enhanced risk of atherothrombosis. A strategy to improve anti-inflammatory agents' use in cancer prevention could be to develop tissue-specific drug delivery systems. Platelet ability to interact with tumor cells and transfer their molecular cargo can be employed to design platelet-mediated drug delivery systems to enhance the efficacy and reduce toxicity associated with anti-inflammatory agents in these settings. Another peculiarity of platelets is their capability to uptake proteins and transcripts from the circulation. Thus, cancer patient platelets show specific proteomic and transcriptomic expression profiles that could be used as biomarkers for early cancer detection and disease monitoring.

Prevalence, Risk Factors, and Pathophysiology of Nonalcoholic Fatty Liver Disease (NAFLD) in Women with Polycystic Ovary Syndrome (PCOS)

Background: Polycystic Ovary Syndrome (PCOS) is one of the most common endocrine disorders in women's reproductive period of life. The presence of nonalcoholic fatty liver disease NAFLD, one of the leading causes of chronic liver disease in the Western world, is increased in women with PCOS. This review aims to present current knowledge in epidemiology, pathophysiology, diagnostics, and treatment of NAFLD in PCOS with an emphasis on the molecular basis of development of NAFLD in PCOS women. Methods: Authors investigated the available data on PCOS and NAFLD by a MEDLINE and Pub Med search during the years 1990-2021 using a combination of keywords such as "PCOS", "NAFLD", "steatohepatitis", "insulin resistance", "hyperandrogenaemia", "inflammation", "adipose tissue", and "obesity". Peer-reviewed articles regarding NAFLD and PCOS were included in this manuscript. Additional articles were identified from the references of relevant papers. Results: PCOS and NAFLD are multifactorial diseases, The development of NAFLD in PCOS women is linked to insulin resistance, hyperandrogenemia, obesity, adipose tissue dysfunction, and inflammation. There is the possible role of the gut microbiome, mitochondrial dysfunction, and endocannabinoid system in the maintenance of NAFLD in PCOS women. Conclusions: There is a need for further investigation about the mechanism of the development of NAFLD in PCOS women. New data about the molecular basis of development of NAFLD in PCOS integrated with epidemiological and clinical information could influence the evolution of new diagnostic and therapeutic approaches of NAFLD in PCOS.

Association of Serum Bilirubin and Functional Variants of Heme Oxygenase 1 and Bilirubin UDP-Glucuronosyl Transferase Genes in Czech Adult Patients with Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disorder worldwide. The aim of our study was to assess the role of bilirubin, and the heme oxygenase 1 (HMOX1) and bilirubin UDP-glucuronosyl transferase (UGT1A1) promoter gene variants, which are involved in bilirubin homeostasis, in the NAFLD development in adult patients. The study was performed on 84 patients with NAFLD and 103 age/sex-matched controls. Routine biochemistry, inflammatory markers, adipokines, and the fibrosis/steatohepatitis stage were determined in the NAFLD patients. The (GT)n/(TA)n dinucleotide variations in HMOX1/UGT1A1 gene promoters, respectively, were analyzed by fragment analysis. Compared to controls, serum bilirubin concentrations in NAFLD patients tended to be decreased, while the prevalence of phenotypic Gilbert syndrome was significantly low. Genetic variations in HMOX1 and UGT1A1 gene promoters did not differ between NAFLD patients and controls, and no relationship was found in the NAFLD patients between these gene variants and any of the laboratory or histological parameters. In conclusion, metabolism of bilirubin is dysregulated in NAFLD patients, most likely due to increased oxidative stress, since frequencies of the major functional variants in the HMOX1 or UGT1A1 gene promoters did not have any effect on development of NAFLD in adult patients.

Does naringenin supplementation improve lipid profile, severity of hepatic steatosis and probability of liver fibrosis in overweight/obese patients with NAFLD? A randomised, double-blind, placebo-controlled, clinical trial

BACKGROUND AND OBJECTIVES

Naringenin has been reported to have some promising pharmacological effects on the management of obesity and related metabolic complications including non-alcoholic fatty liver disease (NAFLD). Therefore, the present clinical trial study was done to assess the effects of naringenin supplementation on lipid profile, aminotransferase levels, severity of steatosis, as well as probability of fibrosis in overweight/obese patients with NAFLD.

MATERIALS AND METHODS

This placebo-controlled, parallel randomised, double-blind clinical trial study was conducted on 44 eligible overweight/obese patients with NAFLD (naringenin-treated group (n = 22), control group (n = 22)) referred to the national Iranian oil company (NIOC) Central Hospital, Tehran City, Tehran Province, Iran. Participants were randomly assigned to receive naringenin capsules (100 mg) and identical placebo capsules twice a day, before lunch and dinner, for 4 weeks. The primary outcomes were improvement of liver steatosis and NAFLD fibrosis score (NFS), and secondary outcomes included changes in levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lipid profile.

RESULTS

Naringenin consumption significantly reduced percentages of NAFLD grades (P < .001), as well as, serum levels of triglyceride (TG) (P < .001), total cholesterol (TC) (P = .01), and low-density lipoprotein (LDL) (P = .02) and increased serum level of high-density lipoprotein (HDL) (P = .02) compared with the control group. Even after adjusting for the confounders, the results were significant. However, there were no significant changes in AST, ALT and NFS.

CONCLUSION

Our findings revealed that daily intake of 200 mg of naringenin for 4 weeks had beneficial effects on lipid profile and percentages of NAFLD grades as an indicator for the severity of hepatic steatosis. Although, NFS values and serum levels of aminotransferase enzymes including AST and ALT did not remarkably change.

Non-alcoholic fatty liver disease in diabetes: When to refer to the hepatologist?

Non-alcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases worldwide. A strong relationship exists between NAFLD and diabetes mellitus. There is growing evidence of a mechanistically complex and strong association between the two diseases. Current data also shows that one disease actually leads to worsening of the other and vice versa. Understanding of the various pathophysiological mechanisms involved, natural history and spectrum of these two diseases is essential not only for early diagnosis and management but also for prevention of severe disease forms. Despite the tremendous progress made in recent times in acquiring knowledge about these highly prevalent diseases, the guidelines and recommendations for screening and management of diabetics with NAFLD remain ambiguous. An interdisciplinary approach is required to not only raise awareness of the prevalence of NAFLD in diabetics but also for better patient management. This can help attenuate the development of significant complications, such as cirrhosis, decompensation and hepatocellular carcinoma in these patients, thereby halting NAFLD in its tracks. This review focuses on the pivotal role of primary care physicians and endocrinologists in identification of NAFLD in diabetics in early stages and the role of proactive screening for prompt referral to hepatologist.

Periodontal disease-related nonalcoholic fatty liver disease and nonalcoholic steatohepatitis: An emerging concept of oral-liver axis

Periodontal disease, a chronic inflammatory disease of the periodontal tissues, is not only a major cause of tooth loss, but it is also known to exacerbate/be associated with various metabolic disorders, such as obesity, diabetes, dyslipidemia, and cardiovascular disease. Recently, growing evidence has suggested that periodontal disease has adverse effects on the pathophysiology of liver disease. In particular, nonalcoholic fatty liver disease, a hepatic manifestation of metabolic syndrome, has been associated with periodontal disease. Nonalcoholic fatty liver disease is characterized by hepatic fat deposition in the absence of a habitual drinking history, viral infections, or autoimmune diseases. A subset of nonalcoholic fatty liver diseases can develop into more severe and progressive forms, namely nonalcoholic steatohepatitis. The latter can lead to cirrhosis and hepatocellular carcinoma, which are end‐stage liver diseases. Extensive research has provided plausible mechanisms to explain how periodontal disease can negatively affect nonalcoholic fatty liver disease and nonalcoholic steatohepatitis, namely via hematogenous or enteral routes. During periodontitis, the liver is under constant exposure to various pathogenic factors that diffuse systemically from the oral cavity, such as bacteria and their by‐products, inflammatory cytokines, and reactive oxygen species, and these can be involved in disease promotion of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Also, gut microbiome dysbiosis induced by enteral translocation of periodontopathic bacteria may impair gut wall barrier function and promote the transfer of hepatotoxins and enterobacteria to the liver through the enterohepatic circulation. Moreover, in a population with metabolic syndrome, the interaction between periodontitis and systemic conditions related to insulin resistance further strengthens the association with nonalcoholic fatty liver disease. However, most of the pathologic links between periodontitis and nonalcoholic fatty liver disease in humans are provided by epidemiologic observational studies, with the causal relationship not yet being established. Several systematic and meta‐analysis studies also show conflicting results. In addition, the effect of periodontal treatment on nonalcoholic fatty liver disease has hardly been studied. Despite these limitations, the global burden of periodontal disease combined with the recent nonalcoholic fatty liver disease epidemic has important clinical and public health implications. Emerging evidence suggests an association between periodontal disease and liver diseases, and thus we propose the term periodontal disease–related nonalcoholic fatty liver disease or periodontal disease–related nonalcoholic steatohepatitis. Continued efforts in this area will pave the way for new diagnostic and therapeutic approaches based on a periodontologic viewpoint to address this life‐threatening liver disease.

The association of the adipokine zinc-alpha2-glycoprotein with non-alcoholic fatty liver disease and related risk factors: A comprehensive systematic review

BACKGROUND AND AIM

The adipokine zinc-alpha2-glycoprotein (ZAG), a multidisciplinary protein, is involved in lipid metabolism, glucose homeostasis and energy balance. Accumulating evidence demonstrates that the expression of ZAG is mainly downregulated in obesity and obesity-related conditions. In the present study, we assessed the association of ZAG with non-alcoholic fatty liver disease (NAFLD) and the related risk factors including obesity, metabolic factors and inflammatory parameters, with emphasis on potential mechanisms underlying these associations.

METHODS

PRISMA guidelines were followed in this review. Systematic searches were performed using the PubMed/Medline, ScienceDirect, Scopus, EMBASE, ProQuest and Google Scholar databases, up to August 2020 for all relevant published papers.

RESULTS

Out of 362 records screened, 34 articles were included in the final analysis. According to the studies reviewed here, ZAG appears to exert a protective effect against NAFLD by enhancing mRNA expression levels of peroxisome proliferator-activated receptor α (PPARα) and PPARγ, promoting mRNA expression levels of the lipolysis-related genes, reducing mRNA expression levels of the lipogenesis-related genes, increasing hepatic fatty acid oxidation, ameliorating hepatic steatosis, promoting the activity of brown adipose tissue and the expression of thermogenesis-related genes, modulating energy balance and glucose homeostasis, and elevating plasma levels of healthy adipokines such as adiponectin. ZAG can also be involved in the regulation of inflammatory responses by attenuation of the expression of pro-inflammatory and pro-fibrotic mediators.

CONCLUSION

According to the studies reviewed here, ZAG is suggested to be a promising therapeutic target for NAFLD. However, the favourable effects of ZAG need to be confirmed in prospective cohort studies.

Waist-to-height ratio and non-alcoholic fatty liver disease in adults

Background

The waist-to-height ratio (WHtR) has been recognised as a powerful indicator to evaluate non-alcoholic fatty liver disease (NAFLD) in recent years, but few related studies are available. Thus, clarifying the association between the WHtR and NAFLD may be beneficial to the prevention and treatment of NAFLD.

Methods

The cross-sectional study population was from a large-scale health examination programme called ‘human dock’ in Japan. In this study, 14,125 participants in this health examination programme were included. To understand the association between the WHtR and NAFLD more intuitively, we grouped the WHtR values into quintiles and used a multivariable logistic regression model to assess WHtR and its quintile with NAFLD risk. Moreover, we used the generalised additive model to model the association between WHtR and NAFLD to explore their non-linear relationship.

Results

The prevalence of NAFLD among participants in this study was 17.59%, with an average age of 43.53 ± 8.89 years. After adjusting for all non-collinear covariables, we observed a 66% increase in the NAFLD risk per SD increase in WHtR. Furthermore, in the quintile groups of WHtR, the participants in quintile 2, quintile 3, quintile 4, and quintile 5 had 3.62-fold, 5.98-fold, 9.55-fold, and 11.08-fold increased risks of NAFLD, respectively, compared with those in quintile 1 (P_trend < 0.0001). Non-linear relationship analysis revealed threshold and saturation effects between WHtR and NAFLD in which a WHtR of approximately 0.4 might be the threshold effect of NAFLD risk, 0.6 might be the saturation effect of NAFLD risk. Additionally, subgroup analysis showed that the interaction between WHtR and BMI was significant.

Conclusions

Our results suggest that in adults, the WHtR is associated with NAFLD, and the association is not purely linear but non-linear, with significant threshold and saturation effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01824-3.

Joint Effect of Hepatic Steatosis and Alanine Aminotransferase Within the Normal Range on Incident Ischemic Heart Disease: A Prospective Study in Koreans

Purpose

Hepatic steatosis has been associated with some cardiovascular risks. Increased alanine aminotransferase (ALT) was suggested to be linked to endothelial dysfunction. We prospectively investigated the joint effect of hepatic steatosis and elevated ALT within the normal range on incident ischemic heart disease (IHD) risk as an extrahepatic complication.

Patients and Methods

We assessed 16,541 participants without diabetes using data from a health risk assessment study (HERAS) and Korean Health Insurance Review and Assessment (HIRA) data. We defined elevated ALT within the normal range as 30-40 IU/L in men and 23-40 IU/L in women, according to previous Korean epidemiological data. We prospectively assessed hazard ratios (HRs) with 95% confidence intervals (CIs) for IHD using multivariate Cox proportional hazards regression models over a 50-month period after the baseline survey.

Results

During the follow-up period, 368 (2.2%) participants developed IHD. Compared to the group with no hepatic steatosis and controlled ALT, the HRs for IHD were 1.68 (95% CI, 1.16-2.42) in the group with hepatic steatosis and elevated ALT after adjusting for confounding variables.

Conclusion

Hepatic steatosis and elevated ALT levels within the normal range may jointly affect the development of IHD among nondiabetic adults. This indicates that lifestyle advice and vascular health management should be recommended among individuals with hepatic steatosis and elevated ALT, even if it falls within the normal range.

What's New in Hepatic Steatosis

Hepatic steatosis can lead to liver cancer, cirrhosis, and portal hypertension. There are two main types, non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease. The detection and quantification of hepatic steatosis with lifestyle changes can slow the evolution from NAFLD to steatohepatitis. Currently, the gold standard for the quantification of fat in the liver is biopsy, has some limitations. Hepatic steatosis is frequently detected during cross sectional imaging. Ultrasound (US), Computed Tomography (CT), and Magnetic Resonance Imaging (MRI) provide noninvasive assessment of liver parenchyma and can detect fat infiltration in the liver. However, the non-invasive quantification of hepatic steatosis by imaging has been challenging. Recent MRI techniques show great promise in the detection and quantification of liver fat. The aim of this article is to review the utilization of non-invasive imaging modalities for the detection and quantification of hepatic steatosis, to evaluate their advantages and limitations.

Alleviating effects of noni fruit polysaccharide on hepatic oxidative stress and inflammation in rats under a high-fat diet and its possible mechanisms

Non-alcoholic fatty liver disease is associated with gut microbiota, oxidative stress, and inflammation. We aimed to investigate the possible mechanism by which noni fruit polysaccharide (NFP) improved hepatic oxidative stress and inflammation in rats under a high-fat diet (HFD) by modulating short-chain fatty acids (SCFAs), the intestinal barrier, and gut microbiota. Hepatic oxidative stress, inflammation, and gut dysbiosis in rats were induced through HFD feeding for 4 weeks, followed by intervention with NFP treatment (100 mg per kg bw) for 5 weeks. The results showed that NFP reduced body weight gain and improved lipid metabolism, hepatic oxidative stress, and inflammation in rats under a HFD. Aside from these beneficial effects, NFP positively affected the SCFA production and reversed the HFD-induced gut dysbiosis as indicated by improved microbiota diversity and composition. The levels of Lactobacillus, Ruminococcaceae_UCG_014, Parasutterella, [Eubacterium]_coprostanoligenes_group, and Ruminococcus_1 improved, whereas the levels of Prevotella_9, Collinsella, Bacteroides, and Turicibacter decreased. Furthermore, NFP maintained the colonic barrier integrity (increased the mRNA relative expression of CCL5, ZO-1, and occludin in the colon, and decreased the serum CCL5 level), and decreased the serum lipopolysaccharide level. Thus, NFP may modulate the gut microflora and SCFA production and reduce the permeability of the colonic barrier and metabolic endotoxemia, thereby alleviating hepatic oxidative stress and inflammation in rats under a HFD.

Increased risk of acute liver failure by pain killer drugs in NAFLD: Focus on nuclear receptors and their coactivators

Non-alcoholic fatty liver disease (NAFLD) is a global condition characterized by an accumulation of lipids in the hepatocytes. NAFLD ranges from simple steatosis, a reversible and relatively benign condition, to fibrosis with non-alcoholic steatohepatitis (NASH), potentially leading to cirrhosis and hepatocarcinoma. NAFLD can increase the susceptibility to severe liver injury with eventual acute liver failure induced by specific hepatotoxic drugs, including acetaminophen (APAP), which is commonly used as analgesic and antipyretic. Although several animal models have been used to clarify the predisposing role of hepatic steatosis to APAP intoxication, the exact mechanism is still not clear. Here, we shed a light into the association between NAFLD and APAP toxicity by examining the peculiar role of nuclear receptor peroxisome proliferator-activated receptor α (PPARα) and coactivator peroxisome proliferator-activated receptor gamma coactivator 1-β (PGC-1β) in driving fatty acid metabolism, inflammation and mitochondria redox balance. The knowledge of the mechanism that exposes patients with NAFLD to higher risk of acute liver failure by pain killer drug is the first step to eventually claim for a reduction of the maximal diurnal dose of APAP for subjects with liver steatosis.

The Effect of Curcumin Phytosome on the Treatment of Patients with Non-alcoholic Fatty Liver Disease: A Double-Blind, Randomized, Placebo-Controlled Trial

Non-alcoholic fatty liver disease (NAFLD) is a global health problem with increasing prevalence among overweight and obese patients. It is strongly associated with conditions of insulin resistance including type 2 diabetes mellitus (T2DM) and obesity. It has detrimental consequences ranged from simple steatosis to irreversible hepatic fibrosis and cirrhosis. Curcumin is a dietary polyphenol with potential effect in improving NAFLD. Therefore, the aim of this trial was to examine the effect of curcumin supplementation on various aspects of NAFLD. In this trial, a total number of 80 patients were randomised to receive either curcumin at 250 mg daily or placebo for 2 months. Lipid profiles, hepatic enzymes, anthropometric indices and hepatic fat mass were assessed at the baseline and the end of the trial, and compared within the groups. The grade of hepatic steatosis, and serum aspartate aminotransferase (AST) levels were significantly reduced in the curcumin group (p = 0.015 and p = 0.007, respectively) compared to the placebo. There was also a significant reduction in high density lipoprotein (HDL) levels and anthropometric indices in both groups with no significant differences between the two groups. Low dose phospholipid curcumin supplementation each day for 2 months showed significant reduction in hepatic steatosis and enzymes in patients with NAFLD compared to placebo. Further studies of longer duration and higher dosages are needed to assess its effect on other parameters of NAFLD including cardiovascular risk.

Nonalcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis: Current Issues and Future Perspectives in Preclinical and Clinical Research

Nonalcoholic fatty liver disease (NAFLD) is a continuum of liver abnormalities often starting as simple steatosis and to potentially progress into nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis and hepatocellular carcinoma. Because of its increasing prevalence, NAFLD is becoming a major public health concern, in parallel with a worldwide increase in the recurrence rate of diabetes and metabolic syndrome. It has been estimated that NASH cirrhosis may surpass viral hepatitis C and become the leading indication for liver transplantation in the next decades. The broadening of the knowledge about NASH pathogenesis and progression is of pivotal importance for the discovery of new targeted and more effective therapies; aim of this review is to offer a comprehensive and updated overview on NAFLD and NASH pathogenesis, the most recommended treatments, drugs under development and new drug targets. The most relevant in vitro and in vivo models of NAFLD and NASH will be also reviewed, as well as the main molecular pathways involved in NAFLD and NASH development.

Significance of Simple Steatosis: An Update on the Clinical and Molecular Evidence

Non-alcoholic fatty liver disease (NAFLD) is defined clinicopathologically by the accumulation of lipids in >5% of hepatocytes and the exclusion of secondary causes of fat accumulation. NAFLD encompasses a wide spectrum of liver damage, extending from simple steatosis or non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH)—the latter is characterized by inflammation and hepatocyte ballooning degeneration, in addition to the steatosis, with or without fibrosis. NAFLD is now the most common cause of chronic liver disease in Western countries and affects around one quarter of the general population. It is a multisystem disorder, which is associated with an increased risk of type 2 diabetes mellitus as well as liver- and cardiovascular-related mortality. Although earlier studies had suggested that NAFL is benign (i.e., non-progressive), cumulative evidence challenges this dogma, and recent data suggest that nearly 25% of those with NAFL may develop fibrosis. Importantly, NAFLD patients are more susceptible to the toxic effects of alcohol, drugs, and other insults to the liver. This is likely due to the functional impairment of steatotic hepatocytes, which is virtually undetectable by current clinical tests. This review provides an overview of the current evidence on the clinical significance of NAFL and discusses the molecular basis for NAFL development and progression.

Electron microscopic observations in perfusion-fixed human non-alcoholic fatty liver disease biopsies

Non-alcoholic fatty liver disease (NAFLD) is a widespread liver disease in Western society, but its multifactorial pathogenesis is not yet fully understood. Ultrastructural analysis of liver sinusoidal endothelial cells (LSECs) in animal models and in vitro studies shows defenestration early in the course of NAFLD, promoting steatosis. LSECs and fenestrae are important in the transport of lipids across the sinusoids. However, human ultrastructural data, especially on LSECs and fenestrae, are scarce. This study aimed to explore the ultrastructural changes in perfusion type fixed liver biopsies of NAFLD patients with and without non-alcoholic steatohepatitis (NASH), with a special focus on LSECs and their fenestration. Liver biopsies from patients with NAFLD were fixed using two perfusion techniques, jet and injection fixation, for needle and wedge biopsies, respectively. Ultrastructural changes were studied using transmission electron microscopy. NASH was diagnosed by bright-field microscopy using the SAF score (steatosis, activity, fibrosis). Thirty-seven patients were included, of which 12 (32.4%) had NASH. Significantly less defenestration was found in NASH compared to noNASH samples (p=0.002). Other features, i.e., giant mitochondria and fenestrae size did not differ between groups. Furthermore, we described new structures, i.e., single cell steatonecrosis and inflammatory fat follicles (IFF) that were observed in both groups. Concluding, defenestration was more common in noNASH compared to NASH in human liver samples. Defenestration was not related to the degree of steatosis or fibrosis. We speculate that defenestration can be a protective mechanism in simple steatosis which is lacking in NASH.

Role of potato protein hydrolysate and exercise in preventing high-fat diet-induced hepatocyte apoptosis in senescence-accelerated mouse

Nonalcoholic fatty liver disease (NAFLD) is considered to be a serious clinical complication, which could cause significant liver dysfunction including fibrosis, cirrhosis, and cancer. Obesity could lead to NAFLD and contributes to liver disorder and related complicated liver diseases. Effect of exercise combined with alcalase treatment derived potato protein hydrolysate (APPH) on high-fat diet (HFD)-induced hepatic injury was investigated in senescence accelerated mouse-prone 8 (SAMP8) mice in the present study. Mice were divided into six groups (n = 6): Group I-Control, Group II-HFD, Group III-Exercise, Group IV-HFD + APPH, Group V-HFD + Exercise, and Group VI-HFD + Exercise + APPH. Combined APPH treatment and exercise offer better cytoprotection in HFD-induced histological changes than APPH treatment and exercise alone. Further, APPH and exercise activate the cell survival proteins PI3K/Akt and prevent FasL/FADD-mediated apoptosis in HFD fed SAMP8 mouse. APPH with swimming exercise effectively modulate HFD-induced liver damage and apoptosis in aged mice through activation of PI3K/Akt protein. PRACTICAL APPLICATIONS: Exercise training is proven to reduce the health problems associated with aging and obesity, however, intensity and duration of the exercise differs between individuals. We used integrated pharmacological and nonpharmacological approach as a therapeutic strategy for preventing HFD-induced hepatic injury in aged subjects.

The metabolic basis of nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease and is associated with significant morbidity and mortality worldwide, with a high incidence in Western countries and non-Western countries that have adopted a Western diet. NAFLD is commonly associated with components of the metabolic syndrome, type 2 diabetes mellitus and cardiovascular disease, suggesting a common mechanistic basis. An inability to metabolically handle free fatty acid overload-metabolic inflexibility-constitutes a core node for NAFLD pathogenesis, with resulting lipotoxicity, mitochondrial dysfunction and cellular stress leading to inflammation, apoptosis and fibrogenesis. These responses can lead to the histological phenotype of nonalcoholic steatohepatitis (NASH) with varying degrees of fibrosis, which can progress to cirrhosis. This perspective review describes the key cellular and molecular mechanisms of NAFLD and NASH, namely an excessive burden of carbohydrates and fatty acids that contribute to lipotoxicity resulting in hepatocellular injury and fibrogenesis. Understanding the extrahepatic dysmetabolic contributors to NASH is crucial for the development of safe, effective and durable treatment approaches for this increasingly common disease.

Bisphenol-A exposure worsens hepatic steatosis in ovariectomized mice fed on a high-fat diet: Role of endoplasmic reticulum stress and fibrogenic pathways

AIMS

Bisphenol (BP)-A exposure can impair glucose and lipid metabolism. However, it is unclear whether this endocrine disruptor (ED) modulates these processes in postmenopause, a period with organic changes that increase the risk for metabolic diseases. Herein, we evaluated the effects of BPA exposure on adiposity, glucose homeostasis and hepatic steatosis in ovariectomized (OVX) mice fed on a high-fat diet (HFD).

MAIN METHODS

Adult Swiss female mice were OVX and submitted to a normolipidic diet or HFD and drinking water without [control (OVX CTL) and OVX HFD groups, respectively] or with 1 μg/mL BPA (OVX CBPA and OVX HBPA groups, respectively), for 3 months.

KEY FINDINGS

OVX HFD females displayed increased adiposity, glucose intolerance, insulin resistance and moderate hepatic steatosis. This effect was associated with a high hepatic expression of genes involved in lipogenesis (Srebf1 and Scd1), β-oxidation (Cpt1a) and endoplasmic reticulum (ER) stress (Hspa5 and Hyou1). BPA did not alter adiposity or glucose homeostasis disruptions induced by HFD. However, this ED triggered severe steatosis, exacerbating hepatic fat and collagen depositions in OVX HBPA, in association with a reduction in Mttp mRNA, and up-regulation of genes involved in β-oxidation (Acox1 and Acadvl), mitochondrial uncoupling (Ucp2), ER stress (Hyou1 and Atf6) and chronic liver injury (Tgfb1and Casp8). Furthermore, BPA caused mild steatosis in OVX CBPA females, increasing the hepatic total lipids and mRNAs for Srebf1, Scd1, Hspa5, Hyou1 and Atf6.

SIGNIFICANCE

BPA aggravated hepatic steatosis in OVX mice. Especially when combined with a HFD, BPA caused NAFLD progression, which was partly mediated by chronic ER stress and the TGF-β1 pathway.

Post-transplant diabetes mellitus and preexisting liver disease - a bidirectional relationship affecting treatment and management

Liver cirrhosis and diabetes mellitus (DM) are both common conditions with significant socioeconomic burden and impact on morbidity and mortality. A bidirectional relationship exists between DM and liver cirrhosis regarding both etiology and disease-related complications. Type 2 DM (T2DM) is a well-recognized risk factor for chronic liver disease and vice-versa, DM may develop as a complication of cirrhosis, irrespective of its etiology. Liver transplantation (LT) represents an important treatment option for patients with end-stage liver disease due to non-alcoholic fatty liver disease (NAFLD), which represents a hepatic manifestation of metabolic syndrome and a common complication of T2DM. The metabolic risk factors including immunosuppressive drugs, can contribute to persistent or de novo development of DM and NAFLD after LT. T2DM, obesity, cardiovascular morbidities and renal impairment, frequently associated with metabolic syndrome and NAFLD, may have negative impact on short and long-term outcomes following LT. The treatment of DM in the context of chronic liver disease and post-transplant is challenging, but new emerging therapies such as glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter 2 inhibitors (SGLT2i) targeting multiple mechanisms in the shared pathophysiology of disorders such as oxidative stress and chronic inflammation are a promising tool in future patient management.

Citrus reticulata Blanco peel extract ameliorates hepatic steatosis, oxidative stress and inflammation in HF and MCD diet-induced NASH C57BL/6 J mice

Excessive lipid deposition, oxidative stress and inflammation in liver tissues are regarded as crucial inducers of nonalcoholic steatohepatitis (NASH), which is the most frequent chronic liver disease and closely related to obesity and insulin resistance. In this work, the preventive and therapeutic effects of Citrus reticulata Blanco (Jizigan) peel extract (JZE) on NASH induced by high fat (HF) diet and methionine choline-deficient (MCD) diet in C57BL/6 mice were investigated. We found that daily supplementation of JZE with an HF diet effectively ameliorated glucose tolerance and insulin resistance. In addition, the key indexes of lipid profiles, oxidative stress, hepatic steatosis and inflammatory factors were also ameliorated in both NASH mouse models. Furthermore, JZE treatment activated nuclear factor erythroid-2-related factor 2 (Nrf2) in the livers of diet- induced NASH mice. Our study suggests that JZE might alleviate NASH via the activation of Nrf2 signaling and that citrus Jizigan could be used as a dietary therapy for NASH and related metabolic syndrome.

Combined cranberry supplementation and weight loss diet in non-alcoholic fatty liver disease: a double-blind placebo-controlled randomized clinical trial

A double-blind placebo-controlled randomised clinical trial was conducted on 41 patients with non-alcoholic fatty liver disease (NAFLD). Participants were randomly allocated to receive either a cranberry supplement or a placebo for 12 weeks. Both groups were assigned to follow a weight loss diet. At the end of the study, alanine aminotransferase and insulin decreased significantly in both groups (p < .05); however, this reduction was significantly greater in the cranberry group than in the placebo group (p < .05). Significant improvements in insulin resistance were observed in the cranberry group and between the two groups (p < .001 and p = .020, respectively). Also, there was an improvement in steatosis grade and anthropometric measurements in both groups (p < .05), and there was no significant difference between the two groups in regard to these factors (p > .05). It seems that 288 mg of cranberry extract might improve managing NAFLD, which is equivalent to 26 g of dried cranberry.

Challenges and opportunities in drug development for nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are considered major global medical burdens with high prevalence and steeply rising incidence. Despite the characterization of numerous pathophysiologic pathways leading to metabolic disorder, lipid accumulation, inflammation, fibrosis, and ultimately end-stage liver disease or liver cancer formation, so far no causal pharmacological therapy is available. Drug development for NAFLD and NASH is limited by long disease duration and slow progression and the need for sequential biopsies to monitor the disease stage. Additional non-invasive biomarkers could therefore improve design and feasibility of such. Here, the current concepts on preclinical models, biomarkers and clinical endpoints and trial designs are briefly reviewed.

Pyridoxamine improves metabolic and microcirculatory complications associated with nonalcoholic fatty liver disease

OBJECTIVE

We investigated the protective effects of pyridoxamine against metabolic and microcirculatory complications in nonalcoholic fatty liver disease.

METHODS

Nonalcoholic fatty liver disease was established by a high-fat diet administration over 28 weeks. Pyridoxamine was administered between weeks 20 and 28. The recruitment of leukocytes and the number of vitamin A-positive hepatic stellate cells were examined by in vivo microscopy. Laser speckle contrast imaging was used to evaluate microcirculatory hepatic perfusion. Thiobarbituric acid reactive substances measurement and RT-PCR were used for oxidative stress and inflammatory parameters. advanced glycation end products were evaluated by fluorescence spectroscopy.

RESULTS

The increase in body, liver, and fat weights, together with steatosis and impairment in glucose metabolism observed in the nonalcoholic fatty liver disease group were attenuated by pyridoxamine treatment. Regarding the hepatic microcirculatory parameters, rats with high-fat diet-induced nonalcoholic fatty liver disease showed increased rolling and adhesion of leukocytes, increased hepatic stellate cells activation, and decreased tissue perfusion, which were reverted by pyridoxamine. Pyridoxamine protected against the increased hepatic lipid peroxidation observed in the nonalcoholic fatty liver disease group. Pyridoxamine treatment was associated with increased levels of tumor necrosis factor alpha (TNF-α) mRNA transcripts in the liver.

CONCLUSION

Pyridoxamine modulates oxidative stress, advanced glycation end products, TNF-α transcripts levels, and metabolic disturbances, being a potential treatment for nonalcoholic fatty liver disease-associated microcirculatory and metabolic complications.

Therapeutic Effects of Garlic on Hepatic Steatosis in Nonalcoholic Fatty Liver Disease Patients: A Randomized Clinical Trial

BACKGROUND AND AIMS

Emerging evidence suggests that garlic (Allium sativum L.) and its bioactive components can mitigate hepatic steatosis by the modulation of hepatic lipid metabolism. We aimed to assess the efficacy of the garlic administration on hepatic steatosis in patients with NAFLD.

PATIENTS AND METHODS

This clinical trial was conducted on adult patients with ultrasound-diagnosed NAFLD. Eligible participants were randomly assigned, with the use of the stratified blocked procedure, to receive 800 mg garlic or placebo for 15 weeks. The primary outcome was the improvement in the hepatic steatosis diagnosed by ultrasound technique after 15 weeks of intervention.

RESULTS

A total of 110 patients underwent randomization, and 98 patients completed the trial. Twenty-four (51.1%) patients in the garlic group achieved improvement in the hepatic steatosis compared to eight (15.7%) patients in the placebo group with the relative risk of 5.6 (95% CI: 2.17 to 14.5; P=0.001), which remained significant after adjusting for baseline value of hepatic steatosis. There were significant reductions in weight and serum ALT, AST, FBS, Hb A1C, total cholesterol, LDL-cholesterol, and TG concentration with the garlic intake compared to placebo (P<0.05). The results were also significant after adjusting for weight change, energy intake, and physical activity. No serious adverse effects were observed with the garlic intake.

CONCLUSION

The intake of garlic powder was accompanied by a significant improvement in the hepatic steatosis and comorbidity related to this condition among subjects with NAFLD.